cliff is right, the stainless steel ones are the valuable kind but the others are still around 400 $ if in good condition.
They made different kinds of all of them, but to my knowledge the stainless steel are all 48 mm and are all the "better" type.

They worked fine when removed and now I need to sell them. I want to put them on e-bay but don't know how much to ask for. I paid $2k for new ones...

But not for the 48 mm kinds did u??

Thanks for any info